Global Equities Research reports that Google Drive signups are off to a "very strong start, with probably about 35 million to 40 million signups in 15 days."

Google Drive, the company's new cloud storage system that launched on April 24, has picked up a lot of users in a short window of time.

A research note from Trip Chowdhry, managing director of Equity Research at Global Equities Research, reported May 12 that Google Drive signups are off to a "very strong start, with probably about 35 million to 40 million signups in 15 days."

That's a lot of people interested in backing up their files and a lot of storage capacity. It certainly helps to have an established brand such as Google holding your files.

"On a scale of 10, developers (Chowdhry talked to 14 of them) give 6 to Google Drive APIs," Chowdhry said. "Developers are optimistic that Google may fix the Drive API's shortcomings by Google I/O event, which is happening in the last week of June."

Chowdhry estimated that Google Drive thus far may have generated at least $4 million in revenues (5% x 35 million x $2.49 = $4 million per month, he calculated).

"However, at this time Global Equities Research does not have insights into the pricing," he wrote. "We think we will get a better sense when we attend Google I/O."